You don't usually encounter the subject of telepathy outside the world of science fiction. The ability to send your thoughts to someone else seems like a type of magic. But scientists around the world are working on systems that might one day let us communicate with each other just by thinking.

The key to this type of communication is developing a robust computer-brain interface. We will need computers to detect, interpret and send our thoughts through a network to the proper recipient. Computers will also receive, decode and deliver thoughts to the person on the other end of the communication. Strictly speaking, we won't be able to communicate with only our minds -- we'll still depend upon computers to do most of the work.

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Even so, the possibility would revolutionize the entire world. People unable to speak could communicate just as clearly as those who can talk. Patients who are locked in -- paralyzed and unable to have a conversation through other means -- would be able to send signals electronically to talk with doctors and loved ones. Soldiers could send information silently as they complete missions.

Language itself could change drastically as a result. Communicating through ideas could transcend words. Instead of thinking "I'm going out for a run," you could imagine yourself running outside and send that thought out. If you were confused about a concept, you could request help from an expert who could think the solution to you.

It's difficult to imagine the full implications of such a system. But that's OK -- we're still decades away from being able to hold entire conversations with other people through thought. The progress we've made so far has been promising, but the science is still in its infancy.

Let's look at what neurologists have managed to do so far.

Cyborgs and Telepathic Computers

Professor Kevin Warwick works at the Institute for Cybernetics at the University of Reading and is credited with being the first cyborg -- part human, part machine. Warwick's research focuses on human-computer interfaces. Doctors have surgically implanted various cybernetic systems in Professor Warwick's body on several occasions. These systems connected directly to Warwick's nervous system -- doctors wired Warwick's nerves to cybernetic chips.

The systems allowed Warwick to connect electronic devices directly to his body. He could send signals through his nervous system to control various devices. He even had doctors wire his nervous system to his wife's nervous system. Whenever his wife closed her hand into a fist, Warwick would receive nervous system impulses. This experiment proved that with the right hardware, two humans could communicate telegraphically through physical signals converted into nervous system impulses.

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Warwick's systems tapped into the nervous system, but didn't interpret signals from the brain as communication. Scientists at the University of Southampton designed a brain-computer interface that goes one step further. Their systems used subjects wearing electroencephalography (EEG) sensors and LEDs attached to computers.

Here's how it worked: Subject A imagined moving one of his or her arms. The EEG detected the subject's brain activity and sent it to a computer. If Subject A imagined moving the left arm, the computer interpreted it as a zero. An imagined movement of the right arm became a one. Subject A's computer sent each signal to a remote computer attached to an LED lamp -- Subject B would watch the lamp.

The lamp lit up in a series of quick flashes -- one set for a zero and a different set for a one. Each series lasted a couple of seconds and consisted of several flashes. While Subject B was unable to detect consciously which series was flashing at any given time, the subject's brain recorded the series without a problem. An EEG connected to Subject B detected which series the subject saw and sent that information to another computer. This computer would decode the series into either a zero or a one.

Using this system, Subject A could send a series of ones and zeros to Subject B through thought alone. Subject B couldn't interpret these signals consciously -- only by looking at the computer screen could he or she know what information had been sent. But the experiment showed that it's possible to send information through thought.

We're still many years away from being able to send and receive fully fledged thoughts to one another. What kind of problems might pop up if we create the technology needed to build such a system?

Your Thoughts Are Showing

Professor Kevin Warwick poses on a Dalek and holds a tiny RF chip he had surgically implanted in his arm.

There are several practical and ethical problems to consider in regard to thought-based communication. One is that any system will require subjects to undergo extensive training to work properly. How can you send specific thoughts while protecting others? You wouldn't want to broadcast every thought you had to the world at large. We'll need to design a system that is easy to control to keep communication clear and private.

Once humans have the ability to send thoughts, we'll also need to worry about the possibility of people designing system to snoop on conversations. Spying will take on a new element. And then there's the frightening possibility of thought police -- a concept found in many science fiction novels. What protections would need to be in place to keep spies from looking in on our thoughts?

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Since these systems all require a brain-computer interface, there are other ethical issues to consider. A comprehensive system might require you to undergo surgery. You may need sensors implanted in your scalp or even in your brain. This raises concerns about safety -- is it medically responsible to implant sensors into a patient? Assuming the patient isn't suffering from paralysis or some other problem that prevents him or her from speaking, should a doctor perform such surgery?

What about people who don't want to have sensors implanted in their heads? Or people who don't want to communicate through thought? Will people who choose not to adopt this technology fall behind? Will the human race separate into two different species -- cyborgs and traditional humans? And could that lead to even bigger problems? Could we actually experience a communication gap?

Right now, it's impossible to answer these questions. And because the technology is still in its infancy, we have many years to debate the issue and possibly work out solutions in advance.

Learn more about communication and technology by following the links on the next page.

Telepathy is a Curse?

Science fiction author and humorist Douglas Adams mentioned a race of aliens called the Belcebrons in his book, "The Restaurant at the End of the Universe." The aliens became cursed with telepathy -- any thought they did not immediately articulate would be broadcast to neighboring planets. As a result, the Belcebrons became noisy chatterboxes -- speaking constantly in an effort to avoid sending their thoughts to other aliens.

University of Southampton. "Communicating person to person through the power of thought alone :: University of Southampton." Oct. 6, 2009. (March 29, 2010) http://www.soton.ac.uk/mediacentre/news/2009/oct/09_135.shtml